Why Does My Filament Keep Breaking? Fix PLA Filament Snapping!

Looking at how 3D printed parts are made, it’s easy to make the mistake of thinking 3D prints are not very strong. This could not be further from the truth as 3D prints are strong enough to make everything from phone cases to anti-riot shields.

Not to say that 3D prints are indestructible, however. One of the biggest flaws of 3D printing is that it produces parts that are not as strong as those made through traditional manufacturing methods like injection moulding.

Thermoplastics used in 3D printing like PLA and ABS have inherent weaknesses compared to thermoset plastics like silicone used in traditional manufacturing. Thermosets are more durable and less prone to breaking. 

Does this mean you should throw out all your filaments and switch to thermosets? Not quite. Firstly, thermosets can’t be used for 3D printing because they burn rather than melt when heated. That’s why they are thermo-sets. 

On a side note! If you’re looking for a reliable and high-quality 3D printer, we highly recommend the Official Creality Ender 3 V2 Upgraded 3D Printer (Amazon Link).

This printer is an upgraded version of the popular Ender 3 model, with a range of new features and improvements that make it even easier and more convenient to use.

The Ender 3 V2 is an excellent choice for beginners, kids, and experienced users.


Second, and most importantly, you can create strong prints using filament if you follow a few guidelines. 

In this article we explore why filaments break and why your prints turn out weak and consequently break. If you want to know how to stop your filament from snapping and how you can produce stronger prints then this guide has some of the best answers for you.

Why Is My 3D Printer Filament Snapping?

Filament snaps because of three main reasons. Snapping is almost always induced or caused by moisture, UV exposure or poor-quality filament. Moisture absorption is most often the chief reason.

3D printing offers an array of options in terms of what material to use. While different types of filament have their unique properties, almost all share one characteristic to some degree. They all absorb moisture or are hygroscopic. Source

Also, check out Does Filament Brand Matter? Which Brands Are The Best !

How hygroscopy affects filaments

Filaments get weaker when they absorb water. The degree to which filament is affected by moisture depends on the type. Some are more affected than others while some like polyvinyl alcohol, or PVA completely dissolve in water. Source

These are the most hygroscopic filaments:

  1. ABS
  2. Nylon
  3. Polycarbonate (PC)
  4. PETG
  5. PVA
  6. Most flexibles like TPU

PLA, ASA and polypropylene are less hygroscopic

While you might not be able to see the moisture on a filament, you can still tell when it is wet. The most common signs of moisture absorption are steam coming out of the printer, bubbles in the extrusion and of course snapping of the filament.

Why Does My PLA Filament Keep Breaking?

PLA will break if it is wet, or has been exposed to ultraviolet light. Sunlight and ambient humidity are the primary factors that weaken PLA filament and cause it to break.

PLA is inherently brittle or prone to breaking. PLA is made from organic material like cornstarch. It has a low print temperature (180 to 230 degrees celsius) which makes it especially easy to use. This is one of the reasons why it’s so popular as a 3D printing material.

While these are the main strengths of PLA, they are also its biggest weaknesses. The organic material used to produce PLA makes it more biodegradable but it also makes PLA more brittle. 

This makes PLA more likely to break and less ideal for printing objects that are likely to be bent or dropped like phone cases for example. 

PLA will break when it has been consistently exposed to moisture or sunlight for an extended length of time. While it has a shelf life of up to three years, moisture or light will weaken the filament and reduce its lifespan. Check out “Does PLA Have A Shelf Life? How long & How To Store It for A longer Shelf Life!

While PLA might be brittle, it is still possibly the best general purpose filament and there are some steps you can take to prevent the effects of moisture and light absorption on it. 

How Do You Stop PLA Filament From Snapping?

The best way to prevent PLA filament from snapping is to dry it. If it is brittle and breaks when used or handled, the filament is most likely wet. In some cases the snapping may have been caused by exposure to UV light. 

There are several ways to dry filament. Some are more “high-tech” and cost a small initial investment into drying equipment while some are much simpler and make use of equipment you have.

The high tech solution for filament drying is a filament dryer. A filament dryer actively removes moisture from wet filament. 

Dryers work by heating the filament and some come equipped with fans, temperature controls or timers to make the process quicker and less hands on. The main advantage to a filament dryer is you’re less likely to overheat the filament.

The low tech solution for filament drying is to use either an oven or food dehydrator. It’s low tech because you don’t have to buy one but it is more hands on. Here you have to monitor the temperature so you don’t “overcook” the filament. Check out “Is A 3D Printing Filament Dryer Necessary? Cheaper Alternatives!

We also highly recommend that you check out our post “Why Does a 3D Print Become Brittle? How To Fix It!

Why Do My 3D Prints Keep Breaking?

There are several reasons why layer separation or splitting in a 3D print happens. It may be because the layer height is too much, the print temperature is too low, the print speed is too fast, the flow rate is too low or the extruder nozzle is not the correct size. 

All these factors relate to the printer settings. The best way to fix this and prevent your prints from breaking would thus be to check your printer settings and readjust them. This might be lowering the layer height or raising the print temperature for example.

Alternatively, if your prints are breaking it could be because of moisture or light absorption. 

Also, find out How Fragile Are Printers & Prints? Do They Easily Break! (Contributing Factors)

How Do You Stop A Filament From Breaking?

The best way to stop filament from breaking is to always store it in dry, airtight containers. This is to prevent moisture absorption. A further step is to place drying agents that actively absorb moisture in the container.

There are several ways to store filament. The simplest way is to use vacuum storage bags. An alternative option is to build or buy a dry box. A dry box is exactly what it sounds like, an airtight box to store your filament.

For more on this, check out our post “How Long Can Filament Be Left Out? Tips On Storing & Using Leftovers!


I am a very well experienced techie civil engineer who's extensively interested in 3D printing technology and even more captivated by the potential of 3D printing livable structures

Recent Posts